1. No category

Electronic mosquito repellents for preventing mosquito bites
and malaria infection (Review)
Enayati A, Hemingway J, Garner P
This is a reprint of a Cochrane review, prepared and maintained by The Cochrane Collaboration and published in The Cochrane Library
2010, Issue 3
http://www.thecochranelibrary.com
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
TABLE OF CONTENTS
HEADER . . . . . . . . . .
ABSTRACT . . . . . . . . .
PLAIN LANGUAGE SUMMARY .
BACKGROUND . . . . . . .
OBJECTIVES . . . . . . . .
METHODS . . . . . . . . .
RESULTS . . . . . . . . . .
DISCUSSION . . . . . . . .
AUTHORS’ CONCLUSIONS . .
ACKNOWLEDGEMENTS
. . .
REFERENCES . . . . . . . .
CHARACTERISTICS OF STUDIES
DATA AND ANALYSES . . . . .
APPENDICES . . . . . . . .
WHAT’S NEW . . . . . . . .
HISTORY . . . . . . . . . .
CONTRIBUTIONS OF AUTHORS
DECLARATIONS OF INTEREST .
SOURCES OF SUPPORT . . . .
INDEX TERMS
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Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
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i
[Intervention Review]
Electronic mosquito repellents for preventing mosquito bites
and malaria infection
Ahmadali Enayati1 , Janet Hemingway2 , Paul Garner3
1 Medical Entomology, School of Public Health and Environmental Health Research Centre, Mazandaran University of Medical
Sciences, Sari, Iran. 2 Liverpool School of Tropical Medicine, Liverpool, UK. 3 International Health Group, Liverpool School of Tropical
Medicine, Liverpool, UK
Contact address: Ahmadali Enayati, Medical Entomology, School of Public Health and Environmental Health Research
Centre, Mazandaran University of Medical Sciences, KM 18 Khazarabad Road, Sari, Mazandaran, 48175-1553, Iran.
[email protected]; [email protected].
Editorial group: Cochrane Infectious Diseases Group.
Publication status and date: Stable (no update expected for reasons given in ’What’s new’), published in Issue 3, 2010.
Review content assessed as up-to-date: 8 March 2009.
Citation: Enayati A, Hemingway J, Garner P. Electronic mosquito repellents for preventing mosquito bites and malaria infection.
Cochrane Database of Systematic Reviews 2007, Issue 2. Art. No.: CD005434. DOI: 10.1002/14651858.CD005434.pub2.
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
ABSTRACT
Background
Electronic mosquito repellents (EMRs) are marketed to prevent mosquitoes biting and to prevent malaria.
Objectives
To assess whether EMRs prevent mosquito bites, and to assess any evidence of an effect on malaria infection.
Search strategy
In March 2009, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL, MEDLINE, EMBASE, LILACS,
Cambridge Scientific Abstracts, and the Science Citation Index. We also checked conference proceedings, contacted international
specialist centres and EMR manufacturers, and checked reference lists.
Selection criteria
Field entomological studies, which controlled for geographic site, time, and attractiveness of human participants, of EMRs for preventing
mosquito bites; and randomized and quasi-randomized controlled trials of EMRs to prevent malaria infection.
Data collection and analysis
Two authors assessed trial quality, and extracted and analysed the data.
Main results
Ten field entomological studies met the inclusion criteria. All 10 studies found that there was no difference in the number of mosquitoes
caught from the bare body parts of the human participants with or without an EMR. No randomized or quasi-randomized controlled
trials on the efficacy of EMR on malaria infection were found.
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
1
Authors’ conclusions
Field entomological studies confirm that EMRs have no effect on preventing mosquito bites. Therefore there is no justification for
marketing them to prevent malaria infection.
PLAIN LANGUAGE SUMMARY
Electronic mosquito repellents for preventing mosquito bites and malaria infection
Malaria is a major health problem that particularly affects people living in sub-Saharan Africa and other tropical parts of the world. It
often causes considerable morbidity and mortality especially in children under five. It is transmitted by mosquito bites from infected
female mosquitoes. Several strategies and approaches are available for preventing mosquito bites and malaria infection, including
repellents, and these approaches will be considered by those living in affected areas and by travellers to areas where there is high risk
of infection. Electronic mosquito repellents (EMRs) are designed to repel female mosquitoes by emitting high-pitched sounds almost
inaudible to the human ear. EMRs are claimed by their manufacturers to be effective in repelling mosquitoes and preventing disease.
No randomized controlled trials were found, but 10 field studies looking at the number of mosquitoes caught on the bare body parts
of humans were assessed. These studies were conducted in various parts of the world with different species of mosquitoes and were
controlled for factors such as locality and timing. One study used just one observer with seven observations, while the highest assessment
included 18 observers with 324 observations. There was no evidence in the field studies to support any repelling effects of EMRs, hence
no evidence to support their promotion or use. Future randomized controlled trials are not proposed as there was no suggestion in the
field studies that EMRs show any promise as a preventive measure against malaria.
BACKGROUND
Malaria affects more than 250 million people and causes more
than a million deaths each year (WHO 2005). One important
control strategy against this and other mosquito-borne diseases is
mosquito control, which aims to reduce human-mosquito contact.
Different control measures are used routinely against mosquitoes
and their larvae, including chemical (eg insecticide), biological (eg
larvivorous fish or pathogenic fungi), environmental (eg land filling or drainage), and personal protection (eg mosquito repellents
formulated as pills, coils, ointments, lotions, and sprays; and insecticide-treated or untreated bed nets).
Electronic mosquito repellents (EMRs) are marketed in response
to a huge demand from the public for convenient, safe, and effective antimosquito products. Female Anopheles mosquitoes transmit malaria by sucking blood from humans, and these small handheld, battery-powered EMRs are intended to repel them by emitting a high frequency buzz almost inaudible to the human ear.
They can be used both indoors and outdoors, and are claimed to
repel mosquitoes within a range of up to 2.5 metres (Kutz 1974;
Helson 1977). No adverse effects have been reported in the literature. Mobile phone companies also market a ring tone that
is claimed to repel mosquitoes within a one-metre radius (BBC
2003).
Some of the EMRs seem to be based on known aspects of mosquito
behaviour, while others have no scientific data to substantiate their
claims. Manufacturers have put forward at least two reasons to
explain the alleged repellent action of sound against mosquitoes.
One reason is that the flight sound of males repels females once
they have been inseminated (Foster 1985); hence, whatever mimics
the males’ flight sound may repel females. However, research has
shown that male mosquitoes are actually the ones attracted by
the female flight sound and females normally have a very weak
sensitivity for sound compared with the males (Wigglesworth
1965; Chapman 1982; McIver 1985; Michelsen 1985). Another
reason is that mosquitoes avoid the ultrasonic cries of bats (Foster
1985). Although both explanations may be conceivable, there is
no published scientific information to support either idea.
Different brands of EMRs have been examined for their efficacy
under laboratory conditions, none of which showed any effects
for the devices tested (Singleton 1977; Curtis 1982; Iglisch 1983;
Foster 1985; Jensen 2000; Andrade 2001; Cabrini 2006). There
are review articles concluding that the EMRs are ineffective in repelling mosquitoes (Coro 1998; Coro 2000). Scientific skepticism
over the last 30 years and a successful prosecution of EMR sellers
under the UK Trade Description Act in 1980s (Curtis 1994; BBC
2005) seems to have done little to deter manufacturers marketing
EMRs and the people who buy them. This is a concern because it
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
2
is likely to lead to consumers not using other protective methods
that are proven to work. This could result in an increased risk of
infection with mosquito-borne diseases, especially malaria (Jensen
2000).
Despite the scientific view and research findings, EMRs are still
widely promoted and used by the public. We therefore decided to
systematically review all reliable research about the effects of highpitched sounds in preventing mosquito bites and, hence, to assess
whether there is any evidence that EMRs have any potential in
preventing malaria in the field setting. We included only field studies since laboratory studies do not reflect influences on mosquito
behaviour, including climate, mosquito density, and composition
of different species in the same locality.
OBJECTIVES
Control
• Dummy EMRs, inoperable EMRs, EMRs switched off, or
no EMRs. We excluded other repellents and treated or untreated
bed nets as control.
• If used, malaria chemoprophylaxis must be identical in
both the intervention and control groups.
Types of outcome measures
• The number of mosquitoes of any species landing on
exposed body parts of humans acting as baits. Time period
defined by entomological collection procedures.
• Malaria infection, defined as clinical malaria (fever with
malaria parasitaemia detected by microscopy or rapid test); or
asymptomatic malaria parasitaemia.
To assess whether EMRs prevent mosquito bites, and to assess
evidence of impact on malaria infection.
Search methods for identification of studies
METHODS
We attempted to locate all relevant studies regardless of language
or publication status (published, unpublished, in press, and in
progress).
Criteria for considering studies for this review
Databases
Types of studies
Preventing mosquito bites
Field entomological studies that control for geographic site (conducted in same locality), time (conducted at same time), and attractiveness of human participants (by rotating participants between the experiments with and without the EMR).
Preventing malaria infection
Randomized and quasi-randomized controlled trials.
Types of participants
Adults or children.
Types of interventions
Intervention
• EMRs with any operational wavelength.
The following databases were searched using the search terms and
strategy described in Appendix 1 : Cochrane Infectious Diseases
Group Specialized Register (March 2009); Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane
Library (2009, Issue 1); MEDLINE (1966 to March 2009); EMBASE (1974 to March 2009); LILACS (1982 to March 2009);
Cambridge Scientific Abstracts (CSA) (1982 to March 2009); and
Science Citation Index (SCI) (1945 to March 2009).
Conference proceedings
The following conference proceedings were searched for relevant
abstracts: XV International Congress of Tropical Medicine and
Malaria, Cartagena, Colombia, August 2000; First MIM PanAfrican Malaria Conference, Dakar, Senegal, 6 to 9 January 1997;
Second MIM Pan-African Malaria Conference, Durban, South
Africa, 15 to 19 March 1999; Third MIM Pan-African Malaria
Conference, Arusha, Tanzania, 17 to 22 November 2002; Fourth
MIM Pan-African Malaria Conference, Yaoundé, Cameroon, 13
to 18 November 2005; International Conference on Entomology, Brisbane, Australia, 15 to 21 August 2004; and Medicine
and Health in the Tropics, Marseille, France, 11 to 15 September
2005.
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
3
Researchers, organizations, and manufacturers
We contacted some corresponding authors and field and clinical
experts (Professor Chris Curtis, London School of Hygiene and
Tropical Medicine; Dr Morteza Zaim, WHO Pesticide Evaluation
Scheme (WHOPES), Geneva, to enquire about other published
or unpublished relevant studies (September 2006). We also contacted EMR manufacturers (Isotronic, Lentek International Inc.,
Electronic Pest Controls Ltd.) for unpublished and ongoing trials
or studies (September 2005).
independently assessed the potentially relevant studies using an
eligibility form based on the inclusion criteria; disagreements were
resolved through discussion.
Data extraction and management
Data collection and analysis
We independently extracted data from all included studies using
a data extraction form and resolved any disagreements in the extracted data by referring to the original paper and through discussion. We described the devices tested and the number of observations made, and assessed the quality of the studies in relation to
whether they controlled for study locality, time of day or night,
participants (used same people to bait mosquitoes), and whether
the observers were blinded. We also assessed the number of times
observations were repeated to gain some quantitative measure of
quality and grouped this with an arbitrary cut off into adequate
(20 or more) or inadequate (less than 20).
Selection of studies
Assessment of risk of bias in included studies
AAE scanned the results of the literature search for potentially
relevant studies and then retrieved the full articles. AAE and PG
We summarized the results of the risk of bias assessment in Table
1.
Reference lists
We also checked the reference lists of all studies identified by the
above methods.
Table 1. Study methodological quality (risk of bias)
Study
Controlled
Observers blind
No. observations
Locality
Time
Bait
Belton 1981
Yes
Yes
Yes
Unclear
Inadequate
Garcia 1976
Yes
Unclear
Unclear
Unclear
Adequate
Gorham 1974
Yes
Yes
Yes
Not blinded
Inadequate
Helson 1977
Yes
Yes
Yes
Unclear
Inadequate
Kutz 1974
Yes
Yes
Yes
Unclear
Inadequate
Lewis 1982
Yes
Yes
Yes
Not blinded
Inadequate
Rasnitsyn 1974
Yes
Yes
Yes
Not blinded
Inadequate
Schreck 1977
Yes
Yes
Yes
Not blinded
Adequate
Snow 1977
Yes
Yes
Yes
Unclear
Inadequate
Sylla 2000
Yes
Yes
Yes
Blinded
Adequate
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
4
Data synthesis
The number of landings on which the rates were calculated varied
considerably according to different ecological and geographical situations, mosquito species, and season and time of day of the tests.
If possible, we would have tested for a difference using the original data to measure a mean difference between arms within one
study and to calculate 95% confidence intervals. Had a difference
been shown, we would also have examined the effects of EMR by
a variety of factors: EMR frequency (< and ≥ 20 kHz); mosquito
population density; malaria endemicity (< and ≥ entomological
inoculation rate of 1/person/night); and mosquito species.
All studies counted mosquitoes landing on the bare body parts
(mostly arms, legs and/or feet) of the human participants for definite time periods with the EMR switched on or off, or, in some
studies, with or without a functional EMR as case and control.
None of the field studies performed in North America and Russia
were on Anopheles mosquitoes; they used Aedes, Culex, Culiseta,
and Mansonia mosquitoes. The two studies in Africa were on
Anopheles as well as other mosquitoes. The lowest number of
observers was one (with 7 observations; Gorham 1974) and the
highest was 18 (with 324 observations; Sylla 2000). Also, timing
and length of collections varied, ranging from one minute (Kutz
1974) to over a 12-hour period (Sylla 2000).
Risk of bias in included studies
RESULTS
Description of studies
See: Characteristics of included studies; Characteristics of excluded
studies.
We identified 18 potentially relevant studies of EMR to prevent
mosquito bites and included 10 (see ’Characteristics of included
studies’ for study details); none were randomized or quasi-randomized controlled trials that used EMR to prevent malaria. We
excluded eight studies because they were only laboratory based or
because they did not provide any data or did not control for locality, time, and blinding (see ’Characteristics of excluded studies’).
The papers for the 10 included studies contained 22 experiments,
of which 15 were field experiments that met the reviews inclusion criteria; the excluded seven experiments were only laboratory
based or used chemical repellents.
Seven studies were carried out in the North America, three in
Canada (Helson 1977; Belton 1981; Lewis 1982) and four in the
USA (Gorham 1974; Kutz 1974; Garcia 1976; Schreck 1977).
Two studies were done in Africa, in Gabon (Sylla 2000) and in
The Gambia (Snow 1977). One study was undertaken in Russia
(Rasnitsyn 1974).
Seven studies gave the commercial name of the EMRs tested (
Rasnitsyn 1974; Helson 1977; Schreck 1977; Snow 1977; Belton
1981; Lewis 1982; Sylla 2000); five studies gave some information
about the ultrasound frequencies used, which ranged from 125 Hz
to 74,600 Hz (Kutz 1974; Belton 1981; Rasnitsyn 1974; Snow
1977; Sylla 2000). The other studies gave no commercial name
and no details of the frequencies used.
As shown in Table 1, all studies made some attempts to control for
locality (geography) of the study area (wooded area, forest, plain,
beach) as they measured landing rates with and without the EMR
in the same geographical area. Different individuals may have different attraction for the mosquitoes, and the studies controlled for
this, usually by swapping the EMR between the participants so
that the same individuals acted as both case and control.
The density of mosquitoes and the intensity with which they attempt to bite varies throughout day and night. Our inclusion criteria required studies to attempt to control for time. This was clearly
described in all but one study (Garcia 1976).
One study blinded the observers to whether they were measuring
during a control or experimental phase (Sylla 2000). The use of
blinding was unclear or not used in the other studies.
In order to test significance, we intended to consider rates per
person in participants in control or intervention areas. As landing
rates were not given per person, we were unable to compare these
data statistically. We recorded the number of times observations
were repeated to gain some insight into data quality, arbitrarily
defining this as adequate (with 20 or more repeated observations or
human participants) and inadequate (less than 20 observations).
Three studies were of adequate quality by this criterion.
Effects of interventions
The number of mosquitoes landing per collection with and without EMR are presented in Table 2. All 10 studies reported that the
landing rates with and without the EMR were little different and
that the EMRs failed to repel mosquitoes. These results occurred
regardless of the study location, mosquito density, mosquito genera, or time of study (ie day or night with day-biting and nightbiting mosquitoes).
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
5
Table 2. Mosquito landing rates
Studya
Landing rate
With EMRb
LR without EMR
Belton 1981
c
c
Garcia 1976
240
193
Gorham 1974
213%d greater than the control
68.78
Helson 1977: ME Electronic Mosquito re- 8.9
pellent
8.4
Helson 1977: Buzz-Off repellent
16.8
14.9
Kutz 1974: Person A
12.2
12.8
Kutz 1974: Person B
16.8
14.2
Lewis 1982
561.5
538
Rasnitsyn 1974
500
497
Schreck 1977: Buzz-Off repellent
25
30
Schreck 1977: Norris Device
36
As above
Snow 1977: Experiment 1
157
140
Snow 1977: Experiment 2
472
425
Snow 1977: Experiment 3
177
155
Sylla 2000
23.4
22.7
a
See ’Characteristics of included studies’ for study details.
crude units, data given in paper.
c Landing rates between 2 and 7/min with no significant difference between groups.
d Based on recalculation of the crude data in the paper.
b Using
No trials were found to assess the effects of EMRs on malaria
infection.
The included studies were of good quality, had controlled for
locality, and all but one had explicitly controlled for time of day or
night, and the human bait for the mosquitoes. The results of this
review provide clear evidence from field-based studies that there
is no hint that these devices have any effect on mosquito landing
DISCUSSION
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
6
rates. The studies reported here examined the effectiveness of the
EMRs with different methods, settings, mosquito species (since
they may respond differently to the high-pitched sounds emitted
by the EMRs), frequencies of the sound emitted by the EMRs
(since mosquitoes may respond to a particular sound wavelength),
and times of day (since day-biting and night-biting mosquitoes
may behave differently to the sound emitted by the EMRs), and
mosquito density (since this may affect EMR efficacy), but none of
them supported the claims of the EMRs’ effectiveness. Although
we did not conduct a meta-analysis of the included studies, there
was no suggestion of difference in landing rates between cases and
controls in any trial. In 12 of the 15 experiments, the landing rates
in the groups with functioning EMR was actually higher than in
the control groups. The absolute number of mosquitoes landing
on the human participants during the experiments while the EMR
was functioning was too high to consider the EMR a repellent.
EMRs are claimed to be effective by mimicking the sound waves
produced by the beating of male mosquitoes’ wings, especially during swarms. Female mosquitoes, which bite humans, are claimed
to be repelled by this sound since they mate only once in their lives.
Hence the repellent mechanism should be based on the hearing
mechanism in females. However, this theory is implausible since
the hearing ability of the females is relatively weak (Wigglesworth
1965; Chapman 1982; Michelsen 1985). It is the hearing system
of males that is relatively strong, and the presence of numerous
sound and vibration receptors (known as Johnston organ) on their
plumose antennae enables them to detect the vibration in the environment as well as the sound of female mosquitoes (Chapman
1982). Thus it is not surprising that the included studies did not
produce any evidence that EMRs act as repellents.
AUTHORS’ CONCLUSIONS
Implications for practice
EMRs are not effective in repelling mosquitoes and should not be
recommended or used.
Implications for research
There is no evidence of an effect of EMRs on landing rates. Thus
there is no evidence that these EMRs could potentially be useful
in preventing malaria in humans. Given these findings from 10
carefully conducted studies, it would not be worthwhile to conduct
further research on EMRs in preventing mosquitoes biting or in
trying to prevent the acquisition of malaria.
ACKNOWLEDGEMENTS
AA Enayati developed the protocol of the review during the Fellowship Programme organized by the Cochrane Infectious Diseases Group in March 2005. The Department for International
Development (DFID) UK supports this Programme through the
Effective Health Care Research Programme Consortium at the
Liverpool School of Tropical Medicine.
This document is an output from a project funded by the DFID
for the benefit of developing countries. The views expressed are
not necessarily those of DFID.
REFERENCES
References to studies included in this review
Belton 1981 {published data only}
Belton P. An acoustic evaluation of electronic mosquito repellers.
Mosquito News 1981;41:751–5.
Garcia 1976 {published data only}
Garcia R, Des Rochers B, Voigt WG. Evaluation of electronic
mosquito repellers under laboratory and field conditions. Vector
Views 1976;23(5/6):21–3.
Gorham 1974 {published data only}
Gorham JR. Tests of mosquito repellents in Alaska. Mosquito News
1974;34:409–15.
Helson 1977 {published data only}
Helson BV, Wright RE. Field evaluation of electronic mosquito
repellers in Ontario. Proceedings of the Entomological Society of
Ontario. 1977; Vol. 108:59–61.
Kutz 1974 {published data only}
Kutz FW. Evaluation of an electronic mosquito repelling device.
Mosquito News 1974;34:369–75.
Lewis 1982 {published data only}
Lewis DJ, Fairchild WL, Leprince DJ. Evaluation of an electronic
mosquito repeller. Canadian Entomologist 1982;114(8):699–702.
Rasnitsyn 1974 {published data only}
Rasnitsyn SP, Alekseev AN, Gornostaeva RM, Kupriianova ES,
Potapov AA. Negative results of test of sound generator devices
designed for mosquito repellence. Meditsinskaia Parazitologiia i
Parazitarnye Bolezni 1974;43(6):706–8.
Schreck 1977 {published data only}
Schreck CE, Weidhaas DE, Smith N. Evaluation of electronic
sound-producing buzzers against Aedes taeniorhynchus and Ae.
solicitans. Mosquito News 1977;37(3):529–31.
Snow 1977 {published data only}
Snow WF. Trials with an electronic mosquito-repelling device in
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
7
West Africa. Transactions of the Royal Society of Tropical Medicine
and Hygiene 1977;71(5):449–50.
Sylla 2000 {published data only}
Sylla el-H K, Lell B, Kremsner PG. A blinded, controlled trial of an
ultrasound device as mosquito repellent. Wiener Klinische
Wochenschrift 2000;112(10):448–50.
References to studies excluded from this review
Andrade 2001 {published data only}
Andrade CFS, Bueno VS. Evaluation of electronic mosquitorepelling devices using Aedes albopictus (Skuse) (Diptera:
Culicidae). Neotropical Entomology 2001;30(3):497–9.
Arevad 1982 {published data only}
Arevad K. Evaluation of an electronic mosquito-repelling device.
Danish Pest Infestation Laboratory Annual Report 1982:21.
Cabrini 2006 {published data only}
Cabrini I, Andrade CFS. Evaluation of seven new electronic
mosquito repellers. Entomologia Experimentalis et Applicata 2006;
121(2):185–8.
Additional references
BBC 2003
S Korean mobiles to zap mosquitoes. news.bbc.co.uk/1/hi/world/
asia-pacific/3063401.stm 14 July 2003.
BBC 2005
Mosquito buzzers’ worth queried. news.bbc.co.uk/1/hi/health/
4218234.stm 6 September 2005.
Chapman 1982
Chapman RF. The insects: structure and function. 3rd Edition.
London: Hodder & Stoughton, 1982.
Coro 1998
Coro F, Suarez S. Electronic repellents against mosquitoes: the
propaganda and the reality [Repelentes electronicos contra
mosquitos: propaganda y realidad]. Revista Cubana de Medicina
Tropical 1998;50(2):89–92.
Coro 2000
Coro F, Suarez S. Review and history of electronic mosquito
repellers. Wing Beats 2000;11(2):6–7.
Curtis 1982 {published data only}
Curtis C, White G. Once bitten, twice shy. New Scientist 1982;93:
328.
Curtis 1994
Curtis CF. Anti-mosquito buzzers, advertising and the law. Wing
Beats 1994;5:10–2.
Foster 1985 {published data only}
Foster WA, Lutes KI. Tests of ultrasonic emissions on mosquito
attraction to hosts in a flight chamber. Journal of the American
Mosquito Control Association 1985;1(2):199–202.
McIver 1985
McIver SB. Mechanoreception. In: Kerkut GA, Gilbert LI editor
(s). Comprehensive insect physiology, biochemistry and pharmacology.
Vol. 6, Oxford: Pergamon, 1985:71–133.
Iglisch 1983 {published data only}
Iglisch VI. Mosquito-repellent efficacy of sound-wave-emitting
apparatus [Zur stechmuckenabweisenden Wirksamkeit von
schallwellenerzeugenden Geraten]. Anzeiger fur Schadlingskde,
Pflanzenschutz, Umweltschutz 1983;56:135–40.
Michelsen 1985
Michelsen A, Larsen ON. Hearing and sound. In: Kerkut GA,
Gilbert LI editor(s). Comprehensive insect physiology, biochemistry
and pharmacology. 6th Edition. Oxford: Pergamon, 1985:
495–556.
Jensen 2000 {published data only}
Jensen T, Lampman R, Slamecka MC, Novak RJ. Field efficacy of
commercial antimosquito products in Illinois. Journal of the
American Mosquito Control Association 2000;16(2):148–52.
WHO 2005
Global Partnership to Roll Back Malaria. World malaria report:
2005. Geneva: World Health Organization, 2005.
Singleton 1977 {published data only}
Singleton RE. Evaluation of two mosquito-repelling devices.
Mosquito News 1977;37(2):195–9.
Wigglesworth 1965
Wigglesworth VB. The principles of insect physiology. 6th Edition.
London: Methuen, 1965.
∗
Indicates the major publication for the study
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
8
CHARACTERISTICS OF STUDIES
Characteristics of included studies [ordered by study ID]
Belton 1981
Methods
Design: field study of experimental intervention versus control
Two human participants with an exposed arm carried out 6 x 5 min catches once with the electronic mosquito
repellent (EMR) switched on and once off
Number of observers: 12
Number of observations: 12
Participants
Human adults
Interventions
1. EMR switched on
2. EMR switched off (control)
EMR suppliers: Murray Distributors Ltd., North Vancouver B.C.; Peak Distributions Ltd., Surrey; Moziquit supplied
by Electronic pest control Ltd., Montreal P.Q.
EMR frequency: 2 to 5 KHz
Outcomes
Aedes and Culex mosquito landing rates/min/participant
Notes
Location: Canada
The raw number of landings with EMR switched off was not provided, but it was mentioned that the differences of
the landing rates with a EMR on and off was not significant
Garcia 1976
Methods
Design: field study of experimental intervention versus control
Catches carried out in 18 different locations in a forest at 2, 5, and 10 min (a total period of 102 min) intervals in
the late afternoon to early evening with electronic mosquito repellent (EMR) on or off
Number of observers: 6
Number of observations: 30
Participants
Human adults
Interventions
1. EMR switched on
2. EMR switched off (control)
EMR supplier: unclear
EMR frequency: not mentioned
Outcomes
Anopheles, Aedes, and Culex mosquito landing rates/person
Notes
Location: USA
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
9
Gorham 1974
Methods
Design: field study of experimental intervention versus control
5 min landing counts carried out on 7 occasions by single catchers with and without electronic mosquito repellent (
EMR)
Number of observers: 1
Number of observations: 7
Participants
Human adults
Interventions
1. EMR
2. No EMR (control)
EMR supplier: not mentioned
EMR frequency: not mentioned
Outcomes
Aedes and Culiseta mosquito landing rates/person/h
Notes
Location: Alaska, USA
Helson 1977
Methods
Design: field study of experimental intervention versus control
Participants 30 m apart in a wooded area caught mosquitoes landing on their arm and hand for 4 min with or without
2 types of electronic mosquito repellent (EMR). So for each, EMR 8 min collection with EMR and 8 min collection
without EMR
Number of observers: 5
Number of observations: 12
Participants
Human adults
Interventions
1. 2 types of EMR
2. No EMR (control)
EMR source: ME Electronic Mosquito Repellent; Buzz-Off repellent
EMR frequency: not mentioned
Outcomes
Aedes mosquito mean landing rate/person
Notes
Location: Canada
Kutz 1974
Methods
Design: field study of experimental intervention versus control
5 x 1 min biting counts made by 2 participants walking 20 paces along a path once with the electronic mosquito
repellent (EMR) on and the other time off
Number of observers: 2
Number of observations: 10
Participants
Human adults
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
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10
Kutz 1974
(Continued)
Interventions
1. EMR switched on
2. EMR switched off (control)
EMR supplier: not mentioned
EMR frequency: 5.2 KHz
Outcomes
Aedes and Culex mosquito mean landing rates/person/min
Notes
Location: USA
Lewis 1982
Methods
Design: field study of experimental intervention versus control
3 participants carried out catches in 3 sites 10 m apart in 4 x 45 min catching experiments each consisting of 3 x
15 min and each of those to 3 x 5-min intervals once with electronic mosquito repellent (EMR) and once without.
Participants with and without EMR were rotated
Number of observers: 3
Number of observations: 12
Participants
Human adults
Interventions
1. EMR
2. No EMR (control)
EMR supplier: Antipic
EMR frequency: not mentioned
Outcomes
Aedes and Mansonia total bites
Notes
Location: Canada
Rasnitsyn 1974
Methods
Design: field study of experimental intervention versus control
3 participants carried 15 observations x 5 min with the electronic mosquito repellent (EMR) on or off
Number of observers: 3
Number of observations: 15
Participants
Human adults
Interventions
1. EMR switched on
2. EMR switched off
EMR supplier: Skeeter Skat, Anti-parasite block, local Russian produced device
EMR frequency: 125 to 74,600 Hz
Outcomes
Aedes, Culiseta, and Culex mosquito landing rates/person/h
Notes
Location: Russia
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
11
Schreck 1977
Methods
Design: field study of experimental intervention versus control
4 participants carried out the catches once without the electronic mosquito repellent (EMR) and once 2 participants
carried one type of EMR and the other 2 two carried other type while walking in a wooded area where Aedes
taeniorhynchus mosquitoes were abundant. They stopped every 20 paces and counted the mosquitoes on their arms.
After each count the mosquitoes were killed to avoid recounting
Number of observers: 4
Number of observations: 44
Participants
Human adults
Interventions
1. 2 types of EMR
2. No EMR (control)
EMR supplier: Buzz-Off; Norris Electronic Mosquito Repeller
EMR frequency: not mentioned
Outcomes
Aedes mosquito landing rate/person
Notes
Location: USA
Snow 1977
Methods
Design: field study of experimental intervention versus control
Experiment 1: 2 teams of 2 catchers each seated 30 m apart. Each catcher collected mosquitoes for 30 minutes at 2
periods during the night. In the first period, the first team were exposed to the electronic mosquito repellent (EMR)
and in the second period, the second team was exposed. Repeated on 2 consecutive nights
Experiment 2: single catchers (1 with EMR and other without) sat 25 m apart and made 2 x 30 min catches over 6
nights, so a total of 2 x 2 x 30 x 6 min catches. EMRs were swapped each night between catchers
Experiment 3: single catchers (1 with EMR and other without) sat 25 m apart made 2 x 30 min catches over 4 nights,
so a total of 2 x 2 x 30 x 4 min catches. EMRs were swapped each night between catchers
Number of observers: 4 (experiment 1); 1 (experiments 2 and 3)
Number of observations: 16 (experiment 1); 12 (experiment 2 and 3)
Participants
Human adults
Interventions
1. EMR
2. No EMR (control)
EMR supplier: Moziquit from Electronic Pest Controls Ltd.
EMR frequency: 2.2.5 KHz
Outcomes
Number of Anopheles, Aedes, and Culex mosquitoes landing
Notes
Location: The Gambia
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
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12
Sylla 2000
Methods
Design: field study of experimental intervention versus control
18 houses chosen and grouped into 9 pairs. Each pair with a pair of working and not working electronic mosquito
repellents (EMRs) that were swapped every night. 18 catches were undertaken in each house, 9 with and 9 without
EMR. So a total of 9 x 9 catches in 18 houses, all together 324 catches each for 12 hours were made which makes a
total catch of 3888 person hours
Number of observers: 18
Number of observations: 324
Participants
Human adults
Interventions
1. Functional EMRs
2. Inoperable EMRs (control)
EMR supplier: Isotronic, Horb, Germany
EMR frequency: 3 to 11 KHz
Outcomes
Anopheles, Aedes, Culex, and Mansonia mosquito landing/house/night
Notes
Location: Gabon
Characteristics of excluded studies [ordered by study ID]
Andrade 2001
Laboratory-based EMR study
Arevad 1982
Field-based EMR, but unclear if time, locality and bait were controlled
Cabrini 2006
Laboratory-based EMR study
Curtis 1982
Laboratory-based EMR study
Foster 1985
Laboratory-based EMR study
Iglisch 1983
Laboratory-based EMR study
Jensen 2000
Field trial but no proper control used; number of caught mosquitoes pooled together for 2 chemical repellents and
EMR such that mosquito landing rates with and without EMR could not be calculated
Singleton 1977
Laboratory-based EMR study
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
13
DATA AND ANALYSES
This review has no analyses.
APPENDICES
Appendix 1. Search methods: detailed search strategiesa
Search set
CIDG SRb
CENTRAL
MEDLINE
EMBASE
LILACS, CAS, SCI
1
mosquito repellent
mosquito*
mosquito*
mosquito$
mosquito
2
mosquito control
repel*
repel*
repel$
repel*
3
-
control
control
control
control
4
-
2 or 3
2 or 3
2 or 3
2 or 3
5
-
1 and 4
1 and 4
1 and 4
1 and 4
6
-
MOSQUITO CON- MOSQUITO CON- ultrasound
TROL
TROL
ultrasound
7
-
5 or 6
INSECT
REPELLENTS
electronic
8
-
electronic
INSECT
BITES device$
AND STINGS/PREVENTION
AND
CONTROL
6 or 7
9
-
device$
5 or 6 or 7 or 8
6 or 7 or 8
5 and 8
10
-
ultrasound
ultrasound
5 and 9
-
11
-
8 or 9 or 10
electronic
-
-
12
-
7 and 11
device$
-
-
13
-
-
10 or 11 or 12
-
-
14
-
-
9 and 13
-
-
a Upper
electronic
case: MeSH or EMTREE heading; lower case: free text term.
Infectious Diseases Group Specialized Register.
b Cochrane
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
14
WHAT’S NEW
Last assessed as up-to-date: 8 March 2009.
15 February 2010
Review declared as stable
Given the current evidence, there appears little justification for further trials of
electronic mosquito repellents and they should not be recommended or used. The
authors therefore do not plan to update this review.
HISTORY
Protocol first published: Issue 3, 2005
Review first published: Issue 2, 2007
9 March 2009
New search has been performed
Search updated. No new studies found
18 August 2008
Amended
Converted to new review format with minor editing.
CONTRIBUTIONS OF AUTHORS
AA Enayati developed and wrote the review. P Garner helped develop the review, developed and applied inclusion and quality criteria,
extracted data, and helped write the review. J Hemingway initiated the review and helped with technical issues. AA Enayati is the
guarantor.
DECLARATIONS OF INTEREST
None known.
SOURCES OF SUPPORT
Internal sources
• Liverpool School of Tropical Medicine, UK.
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
15
External sources
• Department of International Development, UK.
INDEX TERMS
Medical Subject Headings (MeSH)
∗ Anopheles; Electronics; Insect Bites and Stings [∗ prevention & control]; Malaria [∗ prevention & control]; Mosquito Control
[∗ instrumentation]; Population Density
MeSH check words
Animals; Female; Humans
Electronic mosquito repellents for preventing mosquito bites and malaria infection (Review)
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
16